Preheat oven to 400℉.
Bring steaks to room temperature and season with smoked salt and pepper.
Preheat cast-iron skillet on high heat. Add olive oil to hot pan, once oil starts to smoke sear steaks on both sides for 2-3 minutes. Add butter and baste for 30 seconds, then remove steaks and set aside.
In the same skillet reduce heat to medium heat. Add garlic and onions to skillet and sauté for 1 minute, then add cashews and sauté for another minute. Add sweet potatoes and sauté for 5 minutes, stirring frequently.
Add shaved Brussels sprouts, dried cranberries and vinegar to skillet. Sauté for 30 seconds and season to taste with kosher salt and black pepper.
Place steaks on top of sweet potato hash and place in oven for 5-10 minutes. Remove the steaks when thermometer inserted into the thickest part reads 120℉. Check texture of sweet potatoes and remove from oven when soft. Gently mix in feta cheese.
Serve steak with hash and a little extra drizzle of olive oil and sherry vinegar. Enjoy!